Hydrodynamics applied to the management and conservation of marine and coastal ecosystems: Gorgona Island, Colombian Pacific Ocean

Playa Palmeras (Gorgona National Park) is one of the most important sites for sea turtle nesting in South and Central America. Because of the morphological processes affecting the beach, the turtle nests are increasingly exposed to the impact of waves and tides, threatening conservation. A study was made to determine the hydrodynamical processes of the zone adjacent to Playa Palmeras, which affects directly the morphodynamical behavior of the beach and thus the preservation of the nests. Field measurements and numerical modeling were used to obtain the general circulation patterns and thermohaline structure behavior in the area in order to determine the spatial and temporal variability of waves and its effects on the beach. A marked seasonality was found, both in the waves and the currents, influenced mainly by the meridional displacement of the ITCZ (Inter-Tropical Convergence Zone) and an interannual variability of the waves, associated with ENSO (El Nino Southern Oscillation). The flooding levels of the beach were determined and flooding probability maps were made, where safer sites to locate the turtle nests could be identified. These maps serve the officials responsible of monitoring the turtles as a tool to take decisions on moving the nests, since they have flood risk information for any point on the beach. The results show that the middle zone north of the beach is the one with the lowest risk of flooding, therefore the most appropriate zone to relocate nests that are in high risk areas.